Bonnie Harris, the "guest" of the Harrises, refuses to eat raw liver that has been left out at room temperature, trying to ration her water supply instead.
Recalling a recent meal of a tuna-and-egg sandwich and Diet Pepsi, Bonnie feels extreme hunger and thirst but has only her helmet and empty backpack with her.
Eventually, her desperation leads her to contemplate eating the raw liver but she resists by pushing it away and attempting to sleep, troubled by dreams.
Rodney Harris, wearing pajamas, visits Bonnie in the cellar where she's being kept. Bonnie mistakenly believes it's evening, thinking she has been captive for a day now.
Bonnie asks for water, but Rodney demands she eat the liver first, which she finds disgusting but debates internally as he insists it is still good to eat.
She tries to negotiate for fresh liver and water, but Rodney is unyielding, referencing his obsession with "perfect nutritional balance" and leaving angrily when she refuses the old liver.
Upstairs, Emily Harris is showing signs of aging, despite their attempts to delay it with their special meals, and is in pain, desperate for relief.
Rodney denies Bonnie's request for fresh liver, thinking thirst will make her more compliant, but is persuaded by Emily's pain and believing it's safe to push Bonnie to eat.
The Harrises discuss the effect of their diet and whether it is primarily psychological; Roddy assures Emily of the physical benefits they've experienced.
Rodney, later that night, brings a fresh slab of liver for Bonnie from their backup supply after seeing she hasn't touched the first one via video feed.
Emily's distrust of medications, viewing them as dangerous, prompts Roddy to expedite Bonnie's compliance, offering her a small amount of water to pair with the liver.
Bonnie consumes the liver while Roddy fantasizes about how her body will contribute to his and Emily's health, planning to cook and eat parts of her.
Despite her dire situation, Bonnie challenges Rodney, who continues the lie that she's part of a government research project, promising release after nondisclosure agreements.
As Bonnie reluctantly finishes eating the liver, she demands the promised water, with her emotional state finally showing signs of breaking.